Intramolecular rearrangement of the monosaccharide esters of an opioid pentapeptide: formation and identification of novel Amadori compounds related to fructose and tagatose

Horvat, Štefica; Roščić, Maja; Varga-Defterdarović, Lidija; Horvat, Jaroslav

doi:10.1039/a707509j

Cited by 22 publications

(14 citation statements)

References 18 publications

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“…As reported earlier, [21][22][23]26 the equilibrium compositions of the Amadori compounds 1-4 show in water and DMSO solution pyranose and furanose forms, the ␤-pyranose tautomer being the most abundant. Quite surprisingly, DMSO solutions of compounds 1-4 contain at equilibrium a relatively high proportion of the acyclic hydrate form (ca.…”

Section: Resultsmentioning

confidence: 72%

“…[21][22][23] We found that glycation of leucine-enkephalin at the Nterminal induces changes in the peptide conformation and results in total loss of opioid activity in vitro. 24 These findings are not only of theoretical interest since similar adducts with altered interactions with endogenous opioid receptors can be formed during exposure of enkephalins, or other opioid peptides, to glucose in vivo.…”

Section: Introductionmentioning

confidence: 98%

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Study of degradation pathways of Amadori compounds obtained by glycation of opioid pentapeptide and related smaller fragments: Stability, reactions, and spectroscopic properties

Jakas

Horvat

2003

Biopolymers

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Reactions between biological amines and reducing sugars (the Maillard reaction) are among the most important of the chemical and oxidative changes occurring in biological systems that contribute to the formation of a complex family of rearranged and dehydrated covalent adducts that have been implicated in the pathogenesis of human diseases. In this study, chemistry of the Maillard reactions was studied in four model systems containing fructosamines (Amadori compounds) obtained from the endogenous opioid pentapeptide leucine-enkephalin (Tyr-Gly-Gly-Phe-Leu), leucine-enkephalin methyl ester, structurally related tripeptide (Tyr-Gly-Gly), or from amino acid (Tyr). The degradation of model compounds as well as their ability to develop Maillard fluorescence was investigated under oxidative conditions in methanol and phosphate buffer pH 7.4 at two different temperatures (37 and 70 degrees C). At 37 degrees C, glycated leucine-enkephalin degraded slowly in methanol (t(1/2) approximately 13 days) and phosphate buffer (t(1/2) approximately 9 days), producing a parent peptide compound as a major product throughout a three-week incubation period. Whereas fluorescence slowly increased over time at 37 degrees C, incubations off all studied Amadori compounds at 70 degrees C resulted in a rapid appearance of a brown color and sharp increase in AGE (advanced glycation end products)-associated fluorescence (excitation 320 nm/emmision 420 nm) as well as in distinctly higher amounts of fragmentation products. The obtained data indicated that the shorter the peptide chain the more degradation products were formed. These studies have also helped to identify a new chemical transformation of the peptide backbone in the Maillard reaction that lead to beta-scission of N-terminal tyrosine side chain and p-hydroxybenzaldehyde formation under both aqueous and nonaqueous conditions.

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Section: Resultsmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 98%

Study of degradation pathways of Amadori compounds obtained by glycation of opioid pentapeptide and related smaller fragments: Stability, reactions, and spectroscopic properties

Jakas

Horvat

2003

Biopolymers

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“…In fact, the product of the intramolecular transformation of tetrapeptide ester 11 was analogous to the one we observed in our previous work on the monosaccharide ester related to the endogenous opioid pentapeptide. [23] Hydrolysis of compound 15 (0.1  NH 4 OH) afforded N-(1-deoxy--fructopyranos-1-yl)-tetrapeptide 16 (22%) (Scheme 4), indistinguishable by spectroscopic data and optical rotation from compound 16 that was obtained by the reaction of -glucose and Tyr-Pro-Phe-Val in pyridine/ acetic acid for 3 days at 37°C.…”

Section: Intramolecular Reactions Of Monosaccharide Esters Of Di- Trmentioning

confidence: 99%

Novel Ester-Linked Carbohydrate−Peptide Adducts: Effect of the Peptide Substituent on the Pathways of Intramolecular Reactions

Jerić

Horvat

2001

Eur. J. Org. Chem.

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Carbohydrate−peptide conjugates in which D-glucose is linked through an ester linkage to the carboxy group of TyrPro (2), Tyr-Pro-Phe (5) or Tyr-Pro-Phe-Val (11), through the C6 hydroxy group of the sugar moiety were synthesized to examine the utility of this type of monosaccharide modification for peptide prodrugs. Evidence is provided that glycoconjugates 2, 5, and 11 easily undergo intramolecular chemical transformations, subsequent to attack of the free N-ter- [a]

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“…Amadori (4) were synthesized under the conditions described by Horvat et al (1998) [32] and Horvat et al (2007). [33] …”

Section: Methodsmentioning

confidence: 99%

Metal-Binding Ability of Leu-Enkephalin, Related Glycoconjugates and Peptidomimetics

Májer¹,

Vass²,

Roščić³

et al. 2015

Croat. Chem. Acta

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Abstract:Both the chemistry and consequences of the nonenzymatic reaction between reducing sugars and reactive amino groups of amino acids, peptides and proteins (known as the Maillard reaction), have received considerable attention in food and health science fields. This initial reaction results in Amadori and similar products formation, followed by degradation to advanced glycation end products (AGEs). It is well established that AGEs are associated with color and odor of thermally processed or stored food, as well as with pathogen products in a number of diseases. The model systems of early stage Maillard reaction products (MRP) were prepared between endogenous opioid peptide leucine enkephalin (1) and D-glucose / D-glucuronic acid. The complexation ability of prepared MRP with metal ions (Ca 2+ , Zn 2+ , Al 3+ , Pb 2+ and Cu 2+ ) was investigated and compared to the complexation ability of parent peptide using ECD and FTIR spectroscopic measurements.

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Intramolecular rearrangement of the monosaccharide esters of an opioid pentapeptide: formation and identification of novel Amadori compounds related to fructose and tagatose

Cited by 22 publications

References 18 publications

Study of degradation pathways of Amadori compounds obtained by glycation of opioid pentapeptide and related smaller fragments: Stability, reactions, and spectroscopic properties

Study of degradation pathways of Amadori compounds obtained by glycation of opioid pentapeptide and related smaller fragments: Stability, reactions, and spectroscopic properties

Novel Ester-Linked Carbohydrate−Peptide Adducts: Effect of the Peptide Substituent on the Pathways of Intramolecular Reactions

Metal-Binding Ability of Leu-Enkephalin, Related Glycoconjugates and Peptidomimetics

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